1. Field of the Invention
The present invention relates to a device for determining compositions of liquids, e.g., for use in motor vehicle.
2. Description of the Related Art
Devices and methods for determining compositions of liquids for use in motor vehicles are known from the related art. For example, fuel mixtures are being used increasingly in motor vehicles which, in addition to the actual petroleum fuels, may contain an admixture of ethanol and/or other alcohols. Usually parameters of the engine management of the motor vehicle are adapted to the composition of the fuel mixture. For this purpose, however, in many cases knowledge about the composition of the fuel mixture, especially an ethanol/fuel mixture ratio is required. Known measuring methods in this connection are the measurement of absorption, transmission or reflection of microwaves by the fuel mixture.
An example of a device equipped for this purpose is known from the published German patent application document DE 10 2008 044 383 A1. A method is described for determining a composition of a fuel mixture, in which a characteristic profile of a specific response to a microwave irradiation is recorded over a larger frequency range in order to ascertain the properties of the fuel mixture, and based on that, the composition of the fuel mixture is inferred. In particular, a measuring principle of a high-frequency sensor is described for determining the properties of fuel mixtures. An advantage of the method described in DE 10 2008 044 383 A1 is that, in particular, accuracy may be increased using larger frequency ranges so that, for example, alcohol-fuel mixtures, which also contain a water component and/or additives, may be characterized considerably more accurately than with conventional methods.
In the published German patent application document DE 10 2010 029 007, a device is described for determining a composition of a fuel mixture. The device includes at least one housing element, into which at least one inner conductor is introduced. In addition, the device has at least one connecting device for the coupling of microwave signals.
A device and a practical application of a measuring principle for a liquids tester, especially a fuel tester, which permits rapid analysis of the liquid for use in motor vehicles, especially of the fuel mixture, e.g., with regard to the following components: fossil content, ethanol content, water content and further contents, would be desirable. For example, the device and/or the measuring principle should be able to be used for what are referred to as blender pumps, at which, for example, a gas-station customer is able to preselect a fuel quality and/or the composition of the liquid, especially the fuel mixture. Furthermore, the device and/or the measuring principle should permit a diagnosis of the tank contents of flex fuel vehicles in a garage and/or for quality assurance of the fuel offered by gas stations, e.g., in third-world countries and/or emerging countries.